my laptop was using windows 7 befroe and I installed the windows 8 after sometime, I change it back to windows 7.I was using it to play game one time then all of a sudden the screen went black, making some sound too. I shut it fown by force by pressing the switch for a long time. since then the problem have persist till today. if it happens and I reboot it, it comes normal. what is going on with my laptop. guys please I need your help urgently. The machine is dell inspiron.